Loading external images into frames

I am learning about loadmovie.

How do you load a movie on the press of a button - into a specific frame?
A frame that was targeted by the button’s actionscript.

(Basically, I have set up a portfolio flash site. I have all of my images in the .swf so the file is larger than it could be. In the portfolio section of my .swf I have thumbnails that on pressing them go to a different frame within that clip to display the larger version of the image. Naturally, I want to load these larger images in only when the thumbs are clicked on.)

I appreciate any help.

Thank you.